Sear pork Heat oven to 450F.,______,Pat pork dry with paper towels, then season lightly with salt (dont oversalt, as the pork will be wrapped in pancetta) and pepper.,Heat a large cast-iron skillet over medium-high, then add enough oil to barely coat the bottom of the pan and heat until hot but not smoking.,Sear pork until brown on all sides, turning with tongs as each side browns, 6 to 8 minutes total.,Remove from pan and let cool about 15 minutes (if you try to wrap pork while its very hot, the pancetta will slip off).,Pour (or spoon) off excess fat from pan.,Wrap in pancetta Rub pork all over with chopped rosemary.,Lay six pieces of kitchen twine on a clean work surface, putting four in one direction (these will wrap around the pork crosswise so should span the length of the roast) and two across them.,On top of the twine, arrange about 12 slices of pancetta, overlapping them slightly, in a rectangle (it should be about 1 inch larger on all sides than the pork).,Place pork on pancetta and lay remaining pancetta slices on top, again overlapping them slightly, to completely cover pork.,Lay the rosemary sprig on top.,To wrap, use the twine to secure them, tying first from end to end and then around.,(This will make the roast more compact for more even roasting and hold pancetta in place.),Roast Return pork to the skillet and then place in the oven.,Roast, basting occasionally with pan juices, until an instant-read thermometer inserted in the thickest part registers 138F, about 40 to 50 minutes.,Remove from oven and let rest for 10 minutes.,Carve and serve Remove twine.,Slice pork to desired thickness, and serve.,The cooking times provided here are for a 2-pound boneless pork loin that is about 8 inches long and 4 1/2 inches in diameter.,Adjust the roasting time accordingly for thinner or thicker loins.,Pancetta, or Italian cured bacon, lends a distinctive flavor to the roast pork, although any type of bacon can be substituted.,Have your butcher layer the pancetta slices between sheets of paper to keep them from sticking together; thin slices work better (up to a pointtoo thin and they will disintegrate under the intense heat of the oven).,You could roast cipollini onions, or some fruit in the same pan for serving alongside; prunes, apricots (and other stone fruit), apples, and pears all pair wonderfully with pork.